the 'before link-up' image. The Bureau of Engraving and Printing produced the stamps on the Andreotti press in sheets of ninety-six stamps, panes of twenty-four. Quantities issued for this pair of postage issues totaled more than 161 million. Viking missions to Mars, Issue of 1978 NASA's Viking program consisted of a pair of space probes sent to Mars, Viking I and Viking II. Each vehicle was composed of two main parts, an orbiter designed to photograph the surface of Mars from orbit, and a lander designed to study the planet from the surface. The orbiters also served as communication relays for the landers once they touched down. Upon close examination one can discern the engraving of the landing component used to collect soil samples on Mars, the radio dish, landing gear and other equipment rendered by the engraver in this issue. The U.S. Postal Service released this issue at Hampton, Virginia, on July 20, 1978, the second anniversary of the Viking I lander's descent on to the Martian surface. The 15-cent denomination paid the new domestic rate that had recently increased from 13-cents two months earlier for a first-class letter weighing less than half ounce. It was the second such stamp issued to fulfill that rate. Designed by Robert T. McCall, the issue was printed at the Bureau of Engraving and Printing on the Giori presses in sheets of 200 stamps which were then cut into panes of fifty stamps for sale at post offices. First day of issue ceremony took place July 20, 1978, at Hampton, Va. Quantities issued totaled more than 158 million. Space Achievement Issue On May 21, 1981, the Post Office released the Space Achievement commemorative issue, 18-cent stamps, in a block of eight format, one image being shared by four individual stamps, with four more aside them depicting various space exploration imagery. First day of issue occurred at the Kennedy Space Center, Florida. The four central stamps depict the Space Shuttle in its various modes of operation. The central theme of this issue involves the first actual 'in space' flights of the Space Shuttle and also pays tribute to twenty years of U.S. manned space exploration. The other stamps to the left and right sides are honoring the efforts of those who partook in the historical Moon walk, Skylab, and Pioneer 11 missions. The images were modeled by Clarance Holbert. The stamp design by Robert